KR20140123987A - Method for coating pipes - Google Patents

Abstract

The present invention relates to a method for coating the interior of a tube (1), the tube to be coated internally, said method comprising at least the following steps: (i. (Ii) providing an immersion tank 2 suitable for accommodating the tube 1 to be coated and to be coated over its entire length L; (ii.) Immersing the tube 1 to be coated in the coating liquid 3 (Iii) a tube to be coated from the coating liquid (3) while ensuring an angle (alpha) of 1 DEG < (alpha) < 30 DEG between the surface of the coating liquid (3) (Iv) a second immersion step of immersing the tube 1 to be coated in the coating liquid 3; (v.) A step of immersing the center axis M and the coating liquid 3 A second removing step of taking out the tube 1 to be coated from the coating liquid 3 while ensuring an angle beta of -30 DEG < (beta) < -1 DEG between the surfaces, and (vi. (H) of the coating solution (3) in the immersion bath (2) with a viscosity (L) sin (?) And (h) It characterized in that it comprises.

Description

{METHOD FOR COATING PIPES}

The present invention relates to a method for coating the interior of a tube (1), wherein the tube (1)

- an outer surface (a) and an inner surface (b)

- a first tube outer end on the first end of ₍₁₎ (e 1) and the second outer tube end on the second end of (1) (e ₂₎ and,

A length L,

- tube (1) a first end a first inner diameter (D ₁₎ and the tube (1) a second inner diameter (D ₂₎ and on the end of on of,

- a central axis (M). Preferably, the present invention relates to a method for simultaneously coating a plurality of tubes (1) meeting each of the above-listed features.

The present invention relates to a pipe (1) produced according to the method proposed here and to the use of this type of pipe (1) as a transfer pipe for extinguishing agents inside the fire extinguishing system.

The inventors were initially faced with a particular challenge of financing fire prevention facilities, and more precisely, the financing of the design and operation of sprinkler installations. In general, the above-mentioned problem is based on the fact that there is no corrosion even after a relatively long use time and thus can not be subject to a guarantee requirement, and in particular, a tubular material for mild steel and used as a transfer means for fire extinguishing agent is not commercialized .

After numerous deliberations and tests, the inventors were finally able to find a method that could be used to fabricate pipes that fully met the underlying requirements. The method according to the invention is described in the most general form, claiming a method for coating the inside of a tube (1), wherein the tube (1)

- an outer surface (a) and an inner surface (b)

- a first tube outer end on the first end of ₍₁₎ (e 1) and the second outer tube end on the second end of (1) (e ₂₎ and,

A length L,

A first inner diameter D ₁ on the first outer end e ₁ of the tube 1 and a second inner diameter D ₂ on the second outer end e ₂ of the tube 1,

- comprises a central axis (M)

The method according to the invention comprises at least the following method steps:

(i.) providing an immersion tank (2) filled with coating liquid (3) to a filling level (h) and suitable for accommodating the tube (1) to be coated over its entire length (L)

(ii.) a first immersion step of immersing the tube to be coated (1) into the coating liquid (3)

(iii.) A coating liquid (1) is taken out from the coating liquid (3) while ensuring an angle (?) of 1 ° <(?) <30 ° between the central axis (M) and the surface of the coating liquid Removing step,

(iv) a second immersion step of immersing the tube (1) to be coated into the coating liquid (3)

(v.) The tube 1 to be coated is taken out from the coating liquid 3 while ensuring an angle? between -30 ° <(?) <-1 ° between the center axis M and the surface of the coating liquid 3 A second removing step,

(h) of the coating liquid 3 in the immersion bath 2 with (vi) (h)> (L) sin (?) and (h) And a control unit.

This is for economical reasons that when a plurality of tubes 1 simultaneously perform the method steps ii. To vi., That is to say a plurality of tubes 1 simultaneously as well as a single tube 1, The filling level h of the coating liquid 3 in the immersion tank 2 is adjusted so that all the tubes 1 are completely immersed in the coating liquid 3 during the immersion process at the lowest point of the tube 1 3). &Lt; / RTI &gt;

In one preferred embodiment of the method proposed here, the four steps of (ii.) First immersion step, (iii.) First removal step, (iv.) Second immersion step, and (v. The method steps are repeated one to seven iterations, very particularly preferably one to three iterations. This is particularly advantageous if the tube 1 is used up to three times (ii.) A first immersion step, (iii.) A first removal step, (iv.) A second immersion step, and (v. This means that the method steps are performed one after the other.

In a further preferred embodiment of the method proposed herein, the angle alpha is within a distance of 1.8 [deg.] And 5.5 [deg.], And in a more limited manner is within an interval of 1.8 [ This is considered to be desirable at the same time, when the angle [beta] is within the interval of -1.8 [deg.] And -5.5 [deg.], And within the interval of 1.8 [deg.] And 3.5 [deg.] In a more limited manner. Very particularly preferably the angles alpha and beta are selected from the group consisting of (ii.) A first immersion step, (iii.) A first removal step, (iv.) A second immersion step, and (v. The same is true within the four method steps of.

Generally, and preferably in the sense of the present invention, the coating liquid 3 is formed as an aqueous dispersion. In this regard, the inventors have found that the diffusion of the particles provided for the coating during the coating process flows at least in the direction of the inner wall of the tube to be coated, over time, as a permanent feature of the dispersion. In addition, the inventors have found that the use of a preferred coating composition for providing the coating liquid 3 with the inner wall portion (b), in order to ensure a sufficient coating thickness in the preferred range of 15 to 28 탆, very particularly preferably in the range of 21 to 27 탆 We have found that a turbulent flow must be created. In this case, the preferred turbulent flow must meet the task of continuously and continuously contacting the coating particles with the inner wall (b) of the tube 1 to be coated. In other words, for this purpose, not only the desired turbulent flow, but also the coating liquid 3 which passes through the inner wall of the tube to be sufficiently coated must be ensured. A sufficient amount of the coating liquid (3)

First, through the filling level h of the coating liquid 3 in the immersion bath 2 according to the method step (vi.) According to the present invention, and

(Ii) two immersion processes in accordance with the method steps (ii.) To (v.) According to the invention, each being carried out on the one hand with the first outer end e ₁ on the first end of the tube 1 On the other hand, the second outer edge e ₂ on the second end of the tube 1 is located at a relatively lower position during the two immersion processes according to the method steps (ii.) - (v.) According to the invention Through the two immersion processes in which a large amount of coating liquid 3 can be passed through the deeper tube regions through the tube 1 filled with the coating liquid 3 and thus ensured.

After intensive work on which the present invention is based, the inventors have finally found that an interval of 1 DEG to 30 DEG with respect to the angle alpha and an interval of -1 DEG to -30 DEG with respect to the angle [beta] I realized that it is the core. The feature is that the tube to be coated 1 has an angle α of 1 ° <(α) <30 ° compared to a horizontal line extending parallel to the surface of the coating liquid 3 (or -30 ° <β ) &Lt; -1 [deg.]. On the other hand, if there is a risk that the tube 1 will float when immersed in the coating liquid 3, on the other hand, the tube 1 will fall into the coating liquid 3 A sufficient and particularly turbulent flow is not formed during the removal of the tube 1 from the coating liquid 3 as well as during the immersion and thus the direct contact with the inner wall b of the tube 1 A sufficient exchange of the coating liquid 3 becomes impossible. This results in non-uniform, but especially too little, coatings including defect locations. The coating liquid 3 is discharged from the tube 3 through the tube 3 while the tube 3 is immersed in the coating liquid 3 or during the removal of the tube 1 from the coating liquid 3, The time of contact with the inner wall (b) of the inner wall (1) becomes too short to ensure sufficient coating of the inner walls of the tubes, and coating of sufficient thickness. For the preferred angular spacing, the coating thickness and its quality could again be significantly improved.

코팅제일 때 본원의 발명의 매우 특히 바람직한 실시예를 나타냈으며, 특히 900 시리즈 및 이와 똑같이 동일한 유형의 기술을 이용한 가능한 후속 시리즈들의

기법이 매우 특히 바람직한 것으로 간주된다.In principle, a number of different coatings can be envisaged in the application of the methods proposed herein, such as dip coating and parking of the anode and cathode. After extensive and intensive deliberation and testing associated with this speculation, it is believed that in all of the various embodiments within which the coating solution (3) is based on an epoxide / acrylic based

Particularly the preferred embodiment of the invention of the present application, and particularly of the 900 series and possible subsequent series using the same type of technology

Technique is considered to be very particularly desirable.

기법은, 여기서 관(1)의 내벽(b) 상에 화학 기반으로 코팅을 형성할 수 있으며, 이 경우, 원칙적인 유형 및 방식으로, 그리고 본원에서 소개된 발명을 고려하여, 분산액의 형태로 공급되는 FeF₃ 불화철은 금속관(1)의 내부면 표면 상에서 Fe^{2 +} 이온들을 유리시키며, 이 이온들은 마찬가지로 상기 분산액의 형태로 공급된 페인트 입자들과 결합되고 그 다음 다시 금속관(1)의 내부면 표면 상에 용착된다. (ii.) 제1 침지 단계, (iii.) 제1 제거 단계, (iv.) 제2 침지 단계, 및 (v.) 제2 제거 단계의 4가지 방법 단계에 따른 2회 이상의 침지 공정의 주기에 걸쳐서 충분히 길게 조정된 용착 공정의 진행 중에, 상기 방식으로, 15 내지 28㎛의 바람직한 범위, 매우 특히 바람직하게는 21 내지 27㎛의 범위로 층 두께를 보유한 코팅이 형성된다. 900시리즈의 특히 바람직한

기법의 경우, 앞에서 기술한 유형 및 방식으로, 안쪽에 위치하는, 에폭시드/아크릴 기반의 방청 코팅이 형성된다.Developed by Henkel in Düsseldorf, Germany

Technique can form a coating on a chemical basis on the inner wall (b) of the tube (1), in which case, in principle, the type and manner, and in view of the invention introduced here, The FeF ₃ iron fluoride liberates Fe ^{2 +} ions on the inner surface of the metal tube 1 and these ions are likewise combined with the paint particles supplied in the form of the dispersion and then again on the inner surface of the metal tube 1 And is deposited on the surface. (ii) a period of two or more immersion steps according to four method steps of (i) a first immersion step, (iii.) a first removal step, (iv.) a second immersion step, and A coating having a layer thickness in the range of 15 to 28 탆, very particularly preferably in the range of 21 to 27 탆 is formed in this manner during the course of a sufficiently long adjustment of the deposition process over the entire surface of the substrate. Particularly desirable of the 900 series

Technique, an epoxide / acrylic-based rust-inhibiting coating is formed, which is located in the manner and manner previously described.

As a preferred embodiment of the method generally associated with the last two sentences of the preceding paragraph,

- the immersion speed (v ₁ ) for the first immersion step,

- the velocity (v ₂ ) for the first removal step,

- the immersion speed (v ₃ ) for the second immersion step,

- the velocity (v ₄ ) for the second removal step is

Are considered to be preferred when they are each in the range of 6 to 12 m / min. At the same time, under the consideration of the velocities (v ₁ , v ₂ , v ₃ , v ₄ ), with the method steps (ii.) And (v. The filling level h for ensuring complete internal wetting by the coating liquid 3 over the entire tube length L of the tube 1 to be coated during the entire immersion and removal cycle is determined by the amount b) is selected in such a way that the wetting time takes place over a period of from 60 seconds to 210 seconds, very particularly preferably from 85 seconds to 105 seconds.

The coating liquid 3 in the immersion tank 2 is maintained in motion by the circulation device 6, in order to assist the desired turbulent flow in the case of the method proposed here in the tube 1 during coating. The circulation device 6 is preferably a propeller having a low rotational speed.

The method proposed here is not limited in principle with regard to the material and the structural shape of the tube 1 to be coated, but it is preferred, however, to preferentially, therefore, very particularly preferably to longitudinally welded mild steel It is considered to be configured to coat the tube 1 of the material. In the case of this type of pipe 1 the possible length L is limited through the length of the immersion tank 2 preferentially in the case of the process proposed here and the preferred length L is up to 12 m, In a limited manner, it is preferably between 7 and 12 m, very particularly preferably in the range of 7 m to 10 m in length (L). It is also preferred if the first inner diameter D ₁ on the first end of the tube 1 and the second inner diameter D ₂ on the second end of the tube 1 are the same in the range of possible production tolerances, (1) of the above-mentioned type. In this case, the tube (1) has a nominal width (n) of DN 32 to DN 250 within a first preferred range, which is in the range of utilization of fire protection equipment, for example, To sprinkler connection tubes, for example formed as branches (branch conduits), via possible sub-distribution tubes formed as distribution conduits, for example. Within the first preferred range, a range of DN 32 to DN 65 is considered to be very particularly preferred, which, within the scope of the use of fire protection equipment, is dependent on the tube nominal width of the conventional subdistribution tubes up to the sprinkler connection tubes Corresponding. The tube (1) also has a much lower nominal width (n) of DN 15 to DN 32, even within a second preferred range, and the tubes of this type can not, until today, It is not possible to secure an inner wall coating to prevent corrosion.

코팅제로서 형성된 코팅액(3) 내로 침지하는 것을 이용하여 관들 내부에서 관(1)을 코팅하기 위한 본원에서 제안되는 방법 단계들에 선행하여 바람직하게는 특히 중간에 산성 에칭 처리를 이용하는 다단계 탈지 공정이 수행되며, 상기 언급한 모든 처리는 침지조에 의해 구현된다.In the coating liquid (3), especially an epoxide / acrylic based

A multi-stage degreasing process is preferably carried out, preferably in the middle, using an acidic etching process, in advance of the process steps proposed here for coating the tube 1 inside the tubes using immersion into the coating liquid 3 formed as a coating And all the above-mentioned treatments are implemented by an immersion bath.

코팅제로서 형성될 때 유효한다.In a number of tests preceding the present invention, it has been found that each of the tubes 1 to be coated has at least (ii.) A first immersion step, (iii.) A first removal step, (iv.) A second immersion step, and (v. Has been found to be particularly advantageous when gripped by the support holders 4 of the arbor type during the four method steps of the second removal step. Although the arbor type support holders 4 exhibit the drawbacks of reduced friction between the tube 1 and the holder 4 to be coated on the outer surface a of the tube to be coated, Defect locations are very small, which is clearly evidenced as relatively fewer disadvantages. As is preferred, if a plurality of tubes 1 are to perform the method steps ii. To vi. At the same time, this means that the arbor type support holders 4 of this type are part of the immersion frame 5 It is deemed desirable. In this case, the immersion frame 5 can be used together with the arbor type support holders 4 to simultaneously coat a plurality of tubes 1 arranged side-by-side and / or overlapping each other during the coating processes in this case do. Very particularly preferably, in this case, the arbor type support holders 4 and / or the immersion frame 5 are Teflon coated, which is particularly advantageous when the coating liquid 3 is an epoxide / acrylic based

It is effective when it is formed as a coating agent.

코팅이다. 상기 코팅은 매우 특히 바람직하게는, 관(1)의 코팅이 외부뿐 아니라 내부에서도 15 내지 28㎛의 바람직한 범위, 매우 특히 바람직하게는 21 내지 27㎛의 범위의 층 두께를 갖는 방식으로 형성된다.The invention also relates to a tube (1) produced according to the method proposed here, wherein the tube (1) of this type comprises an outer surface rust-preventive coating and an inner surface rust-preventive coating. Preferably, the rust-preventive coating is an epoxide / acrylic-based

Coating. The coating is very particularly preferably formed in such a way that the coating of the tube (1) has a layer thickness in the range of 15 to 28 [mu] m, very particularly preferably in the range of 21 to 27 [mu] m, both internally and externally.

The inventors have focused on the purpose of using the tube 1, such as one produced according to one or more possible embodiments of the method proposed herein, as a transfer tube for the extinguishing agent inside the extinguishing system. In this case, the tube 1, such as that produced according to one or more possible embodiments of the method proposed here, is not only at the start of the initial operation but also within a period of one year after the start of the first operation, very particularly preferably 5 Within the useful life of the year, a value in the range of 125 to 150 for C is achieved. In this case, the value C represents a constant for the type and state of the channel in the Hazen-Williams formula (1) as follows.

P = 6.05 and 10, ⁵ and ^{1 .85} L and Q and C ^(-1.85) and d ^(-4.87)

In the above equation,

P = Pressure loss in conduit [bar],

Q = flow rate through pipeline [l / min],

d = average tube inner diameter [mm],

C = constant representing the type and state of the channel,

L = equivalent length of tube sections and pipe fittings [m].

By providing a value within the range of 125 to 150 for C, a completely flat non-porous sealing is formed on the inner surface of the tube 1, based on the rust-preventive coating formed in this type and located inside, The extinguishing agent guided through the pipe 1 is no longer permeated after several years, and this also applies to the pipe ends of the pipe 1 to be coupled to the coupling.

The tube 1 produced in accordance with the method proposed herein is, in relation to its nominal size, practically unlimited and particularly and preferably the tube 1 must have a nominal width n in the range of DN 32 to DN 250 From the main conduit formed, for example, as a vertical conduit, through a possible subdistribution tube formed, for example, as a distribution conduit, to a sprinkler connection tube formed, for example, as a branch (branch conduit) Which corresponds to the normal tube nominal width. In a very particularly preferred embodiment, the tube 1 should have a nominal width in the range of DN 32 to DN 65, which corresponds to the tube nominal width of a typical subdistribution tube up to the sprinkler connection tube.

1 to 3 substantially describe the present invention.

In Fig. 1 , according to the proposed method, which is rotated by an angle alpha of 1 DEG < (alpha) < 30 DEG with respect to a horizontal line extending parallel to the unshown surface of the coating liquid 3, 1) are shown. Here, the tube 1 considered as a metal tube welded in the longitudinal direction

An outer surface (a) as a surface of the pipe (1) located on the outer side,

An inner surface (b) as an inner wall of the pipe (1)

A length L,

( ₁ ) on the first outer end (e ₁ ), which is located relatively farther below, the first inner diameter (D ₁ ) being relatively higher here, it is equal to the second diameter (D ₂₎ on (e _2).

2 , the same tube 1 as already shown in Fig. 1 is shown (while being observed at the same position), but now the tube 1 has a horizontally extending line extending parallel to the unshown surface of the coating liquid 3 Is different from that shown in Fig. 1 in that it is rotated by an angle beta of -30 DEG < (beta) < What is important here is that, unlike the situation shown in FIG. 1, where one end of the tube 1 (here the first outer end e ₁ ) is located at a relatively lower position, The other end (here the second outer end e ₂ ) is located at a relatively lower position, while the other end of the tube is located at a relatively higher position correspondingly.

3 shows that after the first immersion step of immersing the tube 1 to be coated into the coating liquid 3 according to the method step ii. (iii.) of the method of lifting off the coating liquid 3 while ensuring an angle alpha of < (alpha) < 30 [deg.]. In this case, a more accurate description already in Figure 1, the pipe (1) second end than the first end (e ₁₎ of the (e ₂₎ is, tube (1), the absolute value of [(L) · sin ( α)] is used. In Fig. 3, the tube is partly already located outside the coating liquid 3, and this coating liquid clearly shows the filling level h with (h)> (L) sin (?) Inside the immersion tank 2. [ . In the case shown, a propeller is provided for circulating the coating liquid 3 on the sidewalls of the immersing tank 2 in order to assist the desired turbulent flow in the tube 1 during coating.

In accordance with the following examples , the present invention will be described in substantial detail. To this end, 9m long metal tubes, each welded in the longitudinal direction, are supported on a number of Teflon coated support holders 4 of the Teflon coated immersion frame 5, which are arranged in the DN 15 to DN 32 range Lt; RTI ID = 0.0 &gt; (n). &Lt; / RTI &gt; The immersion frame 5 is supported from above by a ceiling crane which can individually lower or raise the front part as well as the rear part of the immersion frame 5, The respective first ends of the tube 1 supported by the immersion frame 5 and the respective second ends of the tube 1 can be individually lowered or raised. In this case, the tube 1 itself is constructed and spatially oriented as shown in Figs.

코팅제이다. 관(1)의 개별 DN 공칭 폭(n), 침지 각도 및 여기서는 동일한 제거 각도(α=β), (ii.) 제1 침지 단계, (iii.) 제1 제거 단계, (iv.) 제2 침지 단계, 및 (v.) 제2 제거 단계의 4가지 방법 단계에 걸친 반복 횟수, 침지 및 제거를 위한 이송 속도(v₁ = v₂ = v₃ = v₄), 체류 시간, 및 달성된 코팅 두께는 하기의 표 1에 기술된다. 코팅된 관(1)은 끝으로 세정 및 건조된다.In a plurality of submerged baths connected in series, the tube (1) is degreased and intermediate washed. In the further immersion tank 2 constructed as shown in Fig. 3, the supported tube 1 is coated inside thereof, as described and pretreated as described, so that the immersion tank 2 is (h) Is charged to the coating liquid 3 at a charge level h or more of (L) .sin. (Sin) (alpha) and (h) > In this case, the coating solution (3) is a mixture of Henkel 900 series epoxy / acrylic based

It is a coating agent. (N) of the tube 1, the immersion angle and here the same removal angle (? =?), (Ii.) The first immersion step, (iii.) The first removal step, (V ₁ = v ₂ = v ₃ = v ₄ ) for immersion and removal, the residence time, and the number of repetitions over the four method steps of (v ₁ ) The thicknesses are described in Table 1 below. The coated tube 1 is cleaned and dried at the end.

The resulting examples of tests performed assure the implementation of the present invention as clearly as possible. the coating of the inner wall (b) of the tube (1) becomes too small and defect positions and cracks are confirmed, and the same applies to the case where α, -β = 30 ° This is also true for the regions where Within the claimed angular range of 1 ° <(α) <30 ° and -30 ° <(β) <-1 °, the coatings are uniform, and the constant C representing the type and state of the duct in the Hagen- = 125 and is at least above 12.8 탆. Also, within a preferred angular range of 1.8 DEG < (?) <5.5 DEG and -5.5 DEG < (?) &Lt; -1.8 DEG, a coating thickness of 21 mu m with a measured value of C? . The coatings are absolutely uniform, free from any defects, and thus can not penetrate the coating layer over many years. Thereby, the basic task of enabling the use of a general pipe (1), which is free from corrosion even after a longer dwell time and thus enables a financial improvement in the design and operation of fire protection installations, and more precisely sprinkler installations, Is solved.

Claims (24)

A method for coating the interior of a pipe (1), the pipe (1)
- an outer surface (a) and an inner surface (b)
- a first tube outer end on the first end of ₍₁₎ (e 1) and the second outer tube end on the second end of (1) (e ₂₎ and,
A length L,
A first inner diameter D ₁ on the first outer end e ₁ of the tube 1 and a second inner diameter D ₂ on the second outer end e ₂ of the tube 1,
- an inner tube coating method comprising a central axis (M)
The method comprises at least the following method steps:
(i.) providing an immersion tank (2) filled with coating liquid (3) to a filling level (h) and suitable for accommodating the tube (1) to be coated over its entire length (L)
(ii.) a first immersion step of immersing the tube to be coated (1) into the coating liquid (3)
(iii.) A coating liquid (1) is taken out from the coating liquid (3) while ensuring an angle (?) of 1 ° <(?) <30 ° between the central axis (M) and the surface of the coating liquid Removing step,
(iv) a second immersion step of immersing the tube to be coated (1) into the coating liquid (3)
(v.) The tube 1 to be coated is taken out from the coating liquid 3 while ensuring an angle? between -30 ° <(?) <-1 ° between the center axis M and the surface of the coating liquid 3 A second removing step,
(h) of the coating liquid 3 in the immersion bath 2 with (vi) (h)> (L) sin (?) and (h) &Lt; / RTI &gt; wherein the method comprises coating the interior of the tube. Method according to claim 1, characterized in that the method steps (ii.) To (vi.) Are simultaneously carried out in a plurality of tubes (1). The method according to any one of claims 1 to 3, further comprising: (ii) a first immersion step, (iii.) A first removal step, (iv) a second immersion step, and (v. Wherein the step is repeated at a number of repetitions of 1 to 7 times. The method according to any one of claims 1 to 3, further comprising: (ii) a first immersion step, (iii.) A first removal step, (iv) a second immersion step, and (v. Wherein the step is repeated at a number of repetitions of 1 to 3 times. 5. A method according to any one of claims 1 to 4, characterized in that said angle (?) Is within a distance of between 1.8 and 5.5 degrees. 5. A method according to any one of claims 1 to 4, characterized in that the angle (?) Is within a distance of between 1.8 and 3.5 degrees. 7. A method according to any one of claims 1 to 6, characterized in that the angle (?) Is within a distance of between -1.8 ° and -5.5 °. 7. A method according to any one of claims 1 to 6, characterized in that said angle (?) Is within a distance of -1.8 ° and -3.5 °. 9. The method according to any one of claims 1 to 8, wherein the angles (?) And (?) Are selected from the group consisting of (ii.) A first immersion step, (iii.) A first removal step, , And (v.) A second removal step. &Lt; Desc / Clms Page number 12 &gt; Any one of claims 1 to 9, according to any one of claims, wherein the tube (1) a first end a first inner diameter (D ₁₎ and the pipe (1) second end a second inner diameter (D ₂₎ that is the same on the on the &Lt; / RTI &gt; wherein the method comprises the steps of: 11. A coating composition according to any one of claims 1 to 10, wherein the coating liquid (3) is an epoxide / acrylic based

&Lt; / RTI &gt; wherein the coating is a coating agent. 12. A method according to any one of claims 1 to 11, characterized in that the coating liquid (3) in the immersion tank (2) is maintained in motion by the circulation device (6). 13. The method according to any one of claims 1 to 12,
- the immersion speed (v ₁ ) for the first immersion step,
- the velocity (v ₂ ) for the first removal step,
- the immersion speed (v ₃ ) for the second immersion step,
- the velocity (v ₄ ) for the second removal step is
Lt; RTI ID = 0.0 &gt; m / min. &Lt; / RTI &gt; The method of claim 13, wherein the filling level (h) is for 60 seconds to over 210 seconds, the rate of under consideration of _{(v 1, v 2, v} 3, v 4), give total immersion and removal (ii. characterized in that the complete internal wetting by the coating liquid (3) is ensured over the entire tube length (L) of the tube (1) to be coated for at least one time, iii. /// iv., v. / RTI &gt; The method of claim 13, wherein the filling level (h) is, over a period of 85 seconds to 105 seconds, the rate of under consideration of _{(v 1, v 2, v} 3, v 4), give total immersion and removal (ii. characterized in that the complete internal wetting by the coating liquid (3) is ensured over the entire tube length (L) of the tube (1) to be coated for at least one time, iii. /// iv., v. / RTI &gt; 16. A method according to any one of claims 1 to 15, characterized in that the tube (1) has a nominal width (n) in the range of DN 32 to DN 65. 17. A method according to any one of the preceding claims, characterized in that the tube (1) is formed as a mild steel tube with a length (L) ranging from 7 m to 12 m. 18. A method according to any one of claims 1 to 17, wherein the tube to be coated (1) comprises at least (ii.) A first immersion step, (iii.) A first removal step, (iv.) A second immersion step, and (v.) is held by support holders (4) of the arbor type during the four method steps of the second removal step. 19. Method according to claim 18, characterized in that the type of arbor type support holders (4) are parts of an immersion frame (5). Method according to claim 18 and 19, characterized in that the arbor type support holders (4) and / or the immersion frame (5) are Teflon coated. A tube (1) produced by the method according to any one of claims 1 to 20, comprising an outer surface anti-corrosive coating and an inner surface anti-corrosive coating. 22. The method of claim 21, wherein the rust-preventive coating is an epoxide / acrylic-based

(1). &Lt; / RTI &gt; 23. The tube of claim 22, wherein the rust-inhibitive coating has a layer thickness in the range of 15 to 28 mu m. The use of the tube (1) produced by the process according to any one of claims 1 to 20 for use as a transfer tube for extinguishing agents inside the fire extinguishing system.

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